BWW Review: A VERY EXPENSIVE POISON, Old Vic

How theatre should, or should not, be addressing Brexit is a constant topic of conversation. But while Lucy Prebble's phenomenal new work - a combination of horror, espionage thriller, love story and satire, with dazzlingly theatrical framing - doesn't centre around the B world, it is, unquestionably, the play for the present moment.

In 2006, Alexander Litvinenko passed away at University College Hospital, the victim of poisoning by radioactive polonium-210. Prebble's cleverly structured piece has Litvinenko essentially investigate his own murder, with his widow Marina the unwavering voice calling for action - though truth only becomes justice, Prebble suggests, via a good story.

The time-hopping epic, based on Luke Harding's book of the same name, takes us back to Moscow in 1994, with Litvinenko a diligent detective working for the FSB - until his refusal to take politically motivated assassination jobs and to cease investigating FSB officers with links to organised crime leads to harassment, imprisonment, and his family's eventual flight to the UK.

Here, he continues his campaign to expose the evils of Putin's regime, despite the inherent danger - and, while the play illustrates his heroism and virtue, it also questions the cost of pursuing his work, putting at risk his wife and young child. But most of all, it asks us what the real cost is of refusing to recognise wrongdoing and take a moral stand.

The Conservative Government is reluctant to investigate at a time when it's not politically or economically convenient - but are potential trade deals worth the price of a life? Prebble is unflinching in her indictment; Litvinenko was a British citizen when he was murdered on our soil, in a nation he believed offered freedom of speech without fear of reprisal. Dismissing it as a one-off now looks horribly naïve, too, given the recent attack in Salisbury.

It's also impossible to view Litvinenko's death in terms of an abstract ethical conundrum - one unfortunate loss versus wider geopolitical strategy - when Prebble humanises him so effectively. That is the power of theatre, and it's used to wrenching effect here, as we form an affectionate bond with Alexander and wife Marina.

As well as showing their admirable tenacity, MyAnna Buring and Tom Brooke conjure a sweetly teasing, loving, all-too-relatable couple. Seeing Alexander rolling around on the floor with son Anatole, pretending to find a monster in his school bag, while Marina watches on, the horror of this crime becomes palpable and utterly indefensible.

But the play also relates events with sprightly, quick-witted creativity. The "fake news" era (theatre in another form) and the autocrat's repression are cleverly represented by Putin stepping outside of events to question their validity, while vaudevillian touches make the piece's many characters and surreal developments vivid - from songs, puppets and meta gags galore to a lesson on polonium told in rhyme and with shadow play. Even more of these elements would be welcome, particularly in the first half.

A note-perfect ensemble captures the peculiar mix of farce and the macabre; while the hitmen accidentally left a dangerous radioactive trail through central London, their bumbling incompetence is oddly humorous. The high-stakes spy plotting is juxtaposed with matter-of-fact NHS staff treating Litvinenko - and Prebble tells this part of the story with sensitive understatement. The unfeeling "clunk" of a water bottle hitting the bottom of the vending machine, signalling yet another day that Marina is at her dying husband's bedside, lingers on in the memory.

There are brilliant turns from Lloyd Hutchinson, Peter Polycarpou, Amanda Hadingue, Michael Shaeffer, Gavin Spokes, Thomas Arnold, and in particular Reece Shearsmith as a prickly, image-conscious, manipulative Putin. The cast multi-roles superbly, aided by nimble direction from John Crowley, articulate movement by Aletta Collins, and Tom Scutt's fluid, versatile set, which dismantles itself - just as the play deconstructs its own methods in order to understand its subject.

Thoughtfully explored is the sense of damaged pride that leads to the embrace of a strongman leader, in part stemming from Russia's traumatic losses in the Second World War, and the real threat to said leader's power: comedy at their expense. Putin unleashes fury on the Spitting Image puppets, just as Trump does on Saturday Night Live. Perhaps the biggest weapon in Prebble's arsenal is a gift - honed on TV hit Succession - for caustic ridicule.

There are needling one-liners that first make us laugh, then leave a sting, like pointing out Russia's infiltration of the UK via buying up property, football clubs, newspapers, even contributing to cultural institutions like theatres - the sinister flip side to the play's wryly illustrated codes of Englishness. Our culpability in this "soft power" strategy makes this a call to action; what, exactly are we doing with our privileged free speech? Who should we hold to account? Where is the "howl of protest" the situation demands?

Ah, that B word again - and it's a sobering reminder that our place in the world, and ability to take a moral stand, is dependent on factors like economic stability. Crashing out with no deal would mean we're no longer in a position to question the provenance of trade, or the behaviour of our trading partners; an expensive poison indeed.

Litvinenko's downfall begins when he refuses to do something that's illegal "and also wrong". While far too sophisticated to suggest that everything is black and white, Prebble's searing piece fights against a tide of twisted facts, political expediency and public apathy to demand the protection of certain fundamentals - not least truth, however inconvenient. That she uses her medium so adeptly to do so makes this a theatrical triumph.